ePTFE MEMBRANE
Grade
also Gore-Tex
Choose for waterproof-breathable laminates, vents, sterile barrier and 0.02–5 µm liquid/gas microfiltration; very thin (5–100 µm) with strong machine-direction orientation.
Values for the MEMBRANE condition
Other ePTFE grades and fills
ePTFE is listed in 5 conditions; see the grade overview at ePTFE.
Compare all 5 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Carbon-filled / antistatic expanded PTFE | Carbon-black or carbon-fiber loaded ePTFE for static dissipation in solvent/fuel service and for fuel-cell gas-diffusion or electrode substrates. | 5 | 10 | 80 | 50 Shore D |
uniaxially expanded ePTFE cord / tape form-in-place sealant | Pick for large, warped, glass-lined or FRP flanges and manway covers where a cut gasket cannot conform — the cord is laid in place and crushed to shape. | 6 | 25 | 120 | 42 Shore D |
mineral-filled (barium sulfate / silica) expanded PTFE sheet | Use where cold flow / creep relaxation of pure ePTFE is unacceptable: mineral filler raises density and stress-retention at the cost of some conformability. | — | 12 | 100 | 50 Shore D |
ePTFE membrane laminated to PET/PPS/glass scrim (filter media) | Choose for surface-filtration baghouse and HEPA/ULPA media: the ePTFE layer gives >99.99% capture and easy dust release, backing carries the mechanical load. | 12 | 30 | 60 | — |
MEMBRANEThis page microporous ePTFE membrane / breathable film (Gore-Tex type) | Choose for waterproof-breathable laminates, vents, sterile barrier and 0.02–5 µm liquid/gas microfiltration; very thin (5–100 µm) with strong machine-direction orientation. | — | 40 | 120 | — |
What is ePTFE MEMBRANE?
ePTFE MEMBRANE is ePTFE in the MEMBRANE grade — choose for waterproof-breathable laminates, vents, sterile barrier and 0.02–5 µm liquid/gas microfiltration; very thin (5–100 µm) with strong machine-direction orientation. ePTFE MEMBRANE has a tensile strength of 40 MPa (5.8 ksi), weaker than 56% of polymer grades. Elongation at break is 120% and the elastic modulus is 0.6 GPa (0.087 Msi). ePTFE MEMBRANE has a density of 0.4 g/cm³ (0.0145 lb/in³), lighter than 84% of polymer grades. Its glass-transition temperature is 126°C (259 °F).
Advantages
- Good corrosion resistance — 98/100, better than 99% of polymer grades
- Forms and bends easily — 95/100, better than 99% of polymer grades
- High service temperature — 260°C (500 °F), better than 97% of polymer grades
- Low moisture uptake — 0.01%, better than 97% of polymer grades
- Good UV / weathering resistance — 92/100, better than 93% of polymer grades
Limitations
- Difficult to machine — 20/100, worse than 97% of polymer grades
- High embodied carbon — 13 kg CO₂/kg, worse than 93% of polymer grades
- Poor heat conductor — 0.05 W/m·K (0.0289 BTU/hr·ft·°F), worse than 84% of polymer grades
ePTFE MEMBRANE properties
Typical room-temperature values for ePTFE MEMBRANE; 10 are specific to this condition. Other listed values are ePTFE reference data and may not represent this condition. Bars are the position among polymer grades.
Physical4
ePTFE MEMBRANE has a density of 0.4 g/cm³ (0.0145 lb/in³), lighter than 84% of polymer grades. Its glass-transition temperature is 126°C (259 °F).
Mechanical7
ePTFE MEMBRANE has a tensile strength of 40 MPa (5.8 ksi), weaker than 56% of polymer grades. Elongation at break is 120% and the elastic modulus is 0.6 GPa (0.087 Msi).
Thermal8
ePTFE MEMBRANE is rated for continuous service to 260°C (500 °F). It conducts heat at 0.05 W/m·K (0.0289 BTU/hr·ft·°F), worse than 84% of polymer grades. Thermal expansion is 110 µm/m·K (61.1 µin/in·°F).
Electrical6
ePTFE MEMBRANE is an electrical insulator with a dielectric strength of 15 kV/mm (381 V/mil) and a resistivity of 1×10¹⁶ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (98/100), better than 99% of polymer grades. UV resistance is excellent.
Sustainability3
Producing a kilogram of ePTFE MEMBRANE takes about 250 MJ of energy and emits 13 kg of CO₂ — more than 92% of polymer grades. Typical recycled content is 0%.
Manufacturability4
ePTFE MEMBRANE's machinability is poor (20/100, worse than 97% of polymer grades); weldability poor (20/100); formability excellent (95/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ePTFE MEMBRANE
Is ePTFE easy to machine?
Do not turn or mill porous sheet — die-cut, water-jet, slit or ultrasonically cut; use sharp steel-rule dies and back the material to avoid crushing and edge densification.
Can ePTFE be welded?
Not melt-weldable in the usual sense; joints are made by lap-and-sinter above 340 °C, PFA/FEP film bonding, adhesive-backed overlaps or skiving-and-clamping.
Can ePTFE be formed, bent or molded?
Made by paste extrusion/calendering of fine-powder PTFE plus lubricant, lubricant removal, then uniaxial or biaxial stretching at 200–330 °C and optional amorphous locking (sinter) above 340 °C; final parts are cut or laminated rather than molded.
What surface finishes work on ePTFE?
No paint or plating adheres without corona/plasma or sodium-etch pretreatment; typical finishing is adhesive backing (PSA strip), PFA edge sealing, scrim lamination, or hydrophobic/oleophobic surface treatment for vents.
ePTFE chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| processing lubricant (isoparaffin naphth16–25% added for paste extrusion, volatilized before/during expansion | 0 – 0.1 | 0 |
| barium sulfate / silica filleronly in filled (FILLED-MIN) gasket grades | 0 – 40 | 0 |
| carbon black / carbon fiberonly in conductive/antistatic grades | 0 – 20 | 0 |
| PTFE (tetrafluoroethylene homopolymer)fine-powder (paste-extrusion) PTFE resin per ASTM D4895; ePTFE contains no plasticizer after lubricant removal | ≥ 95 (balance) | — |
ePTFE MEMBRANE — frequently asked
What is ePTFE MEMBRANE used for?
ePTFE MEMBRANE is typically used for gasketing sheet/tape for flanges, membrane filters and vents, vascular grafts and medical implants and sealant cord for irregular flanges. In short: most conformable PTFE gasket; lowest-density PTFE form; cut, not machined.
What is the tensile strength of ePTFE MEMBRANE?
ePTFE MEMBRANE has a typical tensile strength of 40 MPa (5.8 ksi) — weaker than 56% of polymer grades. Strength varies by condition: see the 5 listed tempers.
Is ePTFE MEMBRANE easy to machine?
Not especially — machinability is rated poor (20/100, worse than 97% of polymer grades). Do not turn or mill porous sheet — die-cut, water-jet, slit or ultrasonically cut; use sharp steel-rule dies and back the material to avoid crushing and edge densification.
Can ePTFE MEMBRANE be welded?
Not readily — weldability is rated poor (20/100). Not melt-weldable in the usual sense; joints are made by lap-and-sinter above 340 °C, PFA/FEP film bonding, adhesive-backed overlaps or skiving-and-clamping.
What surface finishes work on ePTFE MEMBRANE?
No paint or plating adheres without corona/plasma or sodium-etch pretreatment; typical finishing is adhesive backing (PSA strip), PFA edge sealing, scrim lamination, or hydrophobic/oleophobic surface treatment for vents.
Can ePTFE MEMBRANE be formed, bent or molded?
Made by paste extrusion/calendering of fine-powder PTFE plus lubricant, lubricant removal, then uniaxial or biaxial stretching at 200–330 °C and optional amorphous locking (sinter) above 340 °C; final parts are cut or laminated rather than molded.
What is the maximum service temperature of ePTFE MEMBRANE?
ePTFE MEMBRANE is rated for continuous use to about 260°C (500 °F), and briefly to 300°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM D4895 — PTFE Resin Produced from Dispersion (fine powder) — ASTM International (2018)
- ASTM F36 / F38 — Compressibility & Creep Relaxation of Gasket Materials — ASTM International (2020)
- ASTM F104 — Classification System for Nonmetallic Gasket Materials — ASTM International (2019)
- ASTM D882 / D1708 — Tensile Properties of Thin Plastic Sheeting — ASTM International (2018)
- Expanded PTFE gasket sheet, joint sealant and membrane datasheets — W. L. Gore & Associates / Donaldson / Sumitomo Electric (Poreflon) (2023)
- Engineered Materials Handbook, Vol. 2: Engineering Plastics (PTFE section) — ASM International (1988)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.